The present invention relates to a shoe construction. More particularly, it relates to a shoe configured to conform to, and promote the natural design and movement of, a human foot.
While the invention relates to shoes of all types, discussion hereinafter will focus upon an athletic shoe embodiment. Over the past several decades, the popularity of "high performance" athletic shoes has increased dramatically. In an attempt to capitalize on this demand, athletic shoe manufacturers have devised various design and marketing techniques. For example, athletic shoe manufacturers commonly produce varying styles of shoes for different sports. These include shoes for running, basketball, cross training, wrestling, to name but a few. Each style of shoe is then promoted as having certain attributes designed to enhance an athlete's performance in a particular sport. Additional design and/or marketing techniques include adding brightly-colored materials to the shoe's exterior, supplying extra padding at various locations on or in the shoe, increasing sole thickness, providing inflatable bladders within the shoe, etc.
While each of the above techniques has been met with at least some degree of success, a basic requirement for an athletic shoe may have been overlooked. Namely, for most sport activities, the shoe should conform as close as possible to the natural design and movement of the wearer's foot. For example, the sport of running demands that the athlete's foot be repeatedly lifted and touched to the ground. As the foot touches the ground, a force is imparted. This force, in turn, is transmitted from the ground to the foot, providing energy for subsequent raising of the foot. The running motion further entails a pivoting or flexure motion of the foot at the ball and forward portion. To provide optimal performance when running, an athletic shoe should ultimately be designed so as to minimize energy loss and any interference with the natural pivoting motion.
Unfortunately, many athletic shoe designs fail to account for the natural walking and/or running movement. For example, the bottom or sole portion of the shoe is oftentimes formed of a very thick rubber material. While the rubber material may protect the foot from sharp objects and can be stylized to enhance visual appearance of the shoe, it in fact decreases running efficiency. More specifically, a thick sole acts to absorb energy created by the runner, resulting in a less energy efficient running motion.
Additionally, while the rubber sole may include tread to improve traction, this tread oftentimes impedes the natural motion of the foot. Once again, a natural running motion entails pivoting or flexure of the foot at the ball. Regardless of the amount of traction provided, if the shoe sole is even relatively stiff, it will prevent this natural pivoting action from occurring. This negative affect may be further amplified by the shoe's upper portion. A standard shoe design generally includes a single-piece upper extending from the sole and encompassing the foot. The upper is normally made of relatively stiff leather that resists bending. This resistance to bending directly counteracts the normal flexure at the top of the foot. Thus, the standard shoe design, including a thick sole and relatively rigid upper, impedes natural pivoting and reduces energy efficiency.
An additional problem associated with a standard shoe design is failure to account for an individual wearer's natural foot inclination. It is widely acknowledged that the human foot varies from person to person in both size and instep inclination. Thus, a large number of people have feet which incline either inwardly or outwardly about a central longitudinal axis of the foot. That is to say, many people are either pigeon-toed or slew-footed. The standard shoe design does not take into account this naturally-occurring variation. Instead, the heel portion of a standard shoe design is configured to support the wearer's heel along a relatively horizontal plane. Thus, an athlete who is pigeon-toed or slew-footed will have their foot forced into an unnatural position by the shoe. Obviously, the athlete's natural running motion is negatively impacted, thereby decreasing efficiency.
While styles and designs of athletic shoes continue to evolve, certain basic requirements for efficient running and/or walking motions have not been met. Therefore, a substantial need exists for a shoe construction designed to conform as close as possible to natural foot shape and motion.